1. Technical Field
Aspects of the present invention relate to an image recording device provided with a switch mechanism which switches a driving force between transmission gears connected to drive mechanisms by changing positions of switch gears connected to a motor.
2. Related Art
Conventionally, image recording devices, such as an inkjet printer, have been widely used. The inkjet printer records an image on a recording medium by ejecting ink in accordance with an input signal. More specifically, in the inkjet printer, ink is introduced to actuators in a recording head, and the ink is pressurized and ejected through the effect of deformation of the actuators or the effect of locally boiled ink by heating elements.
The inkjet printer ejects ink selectively from nozzles to form an image on the sheet of paper during a carrying process for carrying the sheet of paper from a paper supply tray to an output tray. The supply of the sheet of paper from the paper supply tray and the carrying of the sheet of paper along a sheet carrying path are performed by providing rollers, such as a supply roller and a carrying roller, to rotate while closely contacting the sheet of paper. In general, a motor, such as a DC motor or a stepping motor, is used as a driving source, and transmission of the driving force from the motor to the rollers is achieved through a transmission mechanism, such as a pinion gear or a timing belt.
There is a possibility that a faulty ejection condition occurs in the ejecting motion of the nozzles, for example, due to air bubbles caused in the nozzles or foreign material lodging in the nozzles. To prevent such a faulty ejection condition, a purge motion is executed in the printer. A maintenance unit for executing the purge motion includes a cap for covering the nozzles of the recording head, and a pump to depressurize the inside of the cap. The motor is also used for driving the pump and a cam for switching the status of an exhaust valve, and the above described transmission mechanism is used for transmitting the drive force from the motor to driving units.
Japanese Patent Provisional Publication No. 2007-90761 (hereafter, referred to as JP2007-90761A) discloses an image recording device provided with a driving force transmission switch unit for switching the driving force from a motor to driving units. The driving force transmission switch unit is configured to selectively transmit the driving force to the driving units. By this structure, it becomes possible to transmit the driving force from a single motor to a supply roller or a carrying roller during image formation, and to transmit the driving force to a maintenance unit during the purge operation.
More specifically, the image recording device disclosed JP2007-90761A is configured as follows. In the following, reference numbers in parentheses correspond to those indicated in JP2007-90761A. In the image recording device disclosed JP2007-90761A, a driving force from a single LF motor (42) is transmitted to a plurality of driving units through the driving force transmission switch unit (100). The driving force transmission switch unit (100) includes a single switch gear (102) and four types of transmission gears including an intermittent supply transmission gear (113), a continuous supply transmission gear (114), a lower stage supply transmission gear (121) and a maintenance transmission gear (115). By positioning a lever part (104a) to one of setting portions 111, 112 and 108, the switch gear (102) engages with corresponding one of the transmission gears to transmit the driving force. The position of the lever part (104a) is set by movement of a carriage (13) in a main scanning direction in accordance with an operation mode.
Japanese Patent Provisional Publication No. HEI 8-174958 (hereafter, referred to as JP HEI 8-174958A) discloses an image recording device configured to have a switch gear, a transmission gear connected to a carrying driving unit, and a transmission gear connected to a purge driving unit. More specifically, in order to smoothly switch the switch gear between the transmission gear connected to the carrying driving unit and the transmission gear connected to the carrying driving unit, the motor is controlled to reciprocate and the switch gear is controlled to reciprocate in the same direction. By this structure, the switch gear is smoothly detached from one of the transmission gear and is smoothly engaged with another transmission gear.